1. Field of the Invention
The present invention concerns a display device and a manufacturing method thereof and, more specifically, it relates to a display device capable of color display using an organic electroluminescence device and a manufacturing method thereof.
2. Description of the Related Art
In organic electroluminescence devices, organic layers such as a hole transporting layer and a light emitting layer are provided between a lower electrode and an upper electrode.
In full color display devices using the organic electroluminescence devices (hereinafter simply referred to as light emitting device), light emitting devices that emit respectively R (ref), G (green), or B (blue) are arranged on a substrate. In manufacturing such devices, it is necessary to provide a light emitting layer comprising an organic light emitting material that emits each color for each light emitting device. Each light emitting layer is provided, for example, by a shadow masking method in which a light emitting material is deposited or coated through a mask provided with a plurality of apertures, or by an ink jet method.
However, it is difficult to further refine or highly integrate the light emitting devices when using the shadow masking method because of the difficulty of refinement of the apertures of the mask due to the distortion of the mask, etc.
Further, patterning with high accuracy is difficult also in the ink jet method.
Then, as a new pattern forming method, a transfer method using an energy source (heat source) (that is, thermal transfer method) has been proposed. A display device is manufactured by the thermal transfer method, for example, as described below. At first, a lower electrode is formed on a substrate of a display device (hereinafter referred to as a device substrate). On the other hand, a light emitting layer is formed by way of a light absorption layer on another substrate (hereinafter referred as a transfer substrate). Then, the device substrate and the transfer substrate are placed in a state of opposing the light emitting layer and the lower electrode and a laser light is irradiated on the side of the transfer substrate thereby thermally transferring the light emitting layer on the lower electrode of the device substrate. In this case, by scanning a laser irradiated spotwise, the light emitting layer is thermally transferred with a good positional accuracy only to a predetermined region on the lower electrode (refer to JP-A No. 2002-110350).